Tobacco smoke filter incorporating coated polyolefin additive



United States Patent 3,428,056 TOBACCO SMOKE FILTER INCORPORATING CUATED POLYOLEFIN ADDITIVE Bobby Jones Snblett and Cephas H. Sloan, Kingsport,

Tenn., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey N 0 Drawing. Continuation-impart of application Ser. No. 447,093, Apr. 9, 1965. This application July 21, 1965, Ser. No. 473,854

US. Cl. 131267 7 Claims Int. Cl. A24d 1/06; A47f 13/06; B01d 27/00 ABSTRACT OF THE DISCLOSURE The selective removal of hydrogen cyanide (HCN) from tobacco smoke is accomplished in a novel filter which has for a base a rod of synthetic fibers forming a fibrous tow such as a cellulose acetate tow, by the incorporation therein of a polyolefin powder on which inorganic water soluble salts are coated, especially the salts of Group Ia elements. Preferred salts include sodium carbonate, sodium phosphite, potassium carbonate and potassium phosphite.

This is a continuation-in-part of our copending application Ser. No. 447,093 filed Apr. 9, 1965.

The present invention relates to tobacco smoke filters which will remove selected vapors from tobacco smoke, and more particularly to a tobacco smoke filter which will remove deleterious materials from tobacco smoke while permitting those vapors that are not deleterious or obnoxious, but which give flavor and taste to the smoke, to readily pass therethrough. This invention further relates to both a novel additive, which when added to a tobacco smoke filter will selectively remove such deleterious components as hydrogen cyanide from the smoke, and to a novel tobacco smoke filter tow that has such additives affixed thereto.

In our US. patent application Ser. No. 425,920, filed Jan. 15, 1965 we disclose the use of certain water-soluble inorganic salts for removing substantial amounts of hydrogen cyanide from tobacco smoke by addition to filter elements. While such salts have proven to be highly successful as hydrogen cyanide removal agents, we have noticed in some instances a tendency of these additives to dust off and/ or to be distributed over the filter filaments in a nonuniform manner. Also, such salts in powder form tend to have particles which are sometimes too large to be completely dissolved by the moisture from the smoke passing through the filter element. Thus, in such instances optimum filtration efliciency is not attained. Therefore, development of a filter element with improved hydrogen cyanide filtration efliciency and an improved water-soluble inorganic salt additive therefor represent a highly desirable result. After extended investigation we have developed an additive which removes an increased amount of hydrogen cyanide from tobacco smoke when used alone or when contained in continuous filament, cellulose acetate filament filter elements. We have also found that this additive may be used in a highly efficient manner in conjunction with certain selected tobacco smoke filter element additives.

Therefore, one object of this invention is to provide a new and improved type of tobacco smoke filter element. Another object is to provide a treated powder which may be applied to a fibrous tow to improve particulate matter removal and to selectively remove hydrogen cyanide (HCN) from the vapor of tobacco smoke. A further object is to provide a method for constructing an improved tobacco smoke filter. Still another object is to provide an improved additive for cellulose acetate filter tow.

In its broader aspects our invention involves adding to cellulose acetate tow powders which have water-soluble inorganic salts coated on the surface thereof, especially the salts of Group Ia elements. The coated powders may be applied onto the tow by vibrating or any other suitable method of even-1y dispersing a dry powder or granular material.

Inorganic salts which We have found particularly useful according to our invention include the sodium and potassium carbonates and phosphites or mixtures of these. Powders (or powders in flake form) which may be coated with these water-soluble inorganic salts to dampen their static properties and thus enhance their application by a vibration technique include polyethylene, polypropylene and other polyolefins which can be processed to a suitable particle size. The amount of inorganic salt that may be added according to our invention is from 1 to 50 percent, the preferred amount being between 2 and 10 percent, based on the weight of the final filter. The amount of additive coated with salt that may be added to the tow according to our invention is between 1 and percent, the preferred amount being between 5 and 50 percent, based on the weight of the final filter.

According to one embodiment of the instant invention a crimped tow may be spread out to a width of approximately 15 inches as it moves through a cigarette plugmaking machine. A vibrating pan- 15 inches in width is placed directly above and parallel to the tow. In the pan is placed a polyolefin powder which has been ground to pass through a SO-mesh screen and coated on its surface (from a water solution) with an inorganic water-soluble salt, the salt coated thereon amounting to 25% by weight of the flake or powder. The vibrator pan is adjusted to apply the desired amount of additive, and the additive is vibrated onto the filter tow as it moves through the filter plug-making equipment. A bonding agent such as gly ceryl triacetate is applied prior to the powdered additive as the tow containing the additive moves through the equipment. The tow is recompacted and wrapped with a paper tape to form a cylindrical-shaped section. After the section has cured to a firm rod, it may be cut into any desired length and used either alone as a filter or in combination with other filters to make a dual or multiple filter.

What is claimed and desired to be secured by the United States Letters Patent is:

1. A rod shaped tobacco smoke filter element comprising compacted synthetic fibers having as an additive thereon a polyolefin powder coated with a water-soluble inorganic salt selected from sodium carbonate, sodium phosphite, potassium carbonate and potassium phosphite.

2. The filter element of claim 1 in which the compacted synthetic fibers are derived from a multifilament tow.

3. The filter element of claim 2 in which the multifilament tow comprises cellulose acetate fibers.

4. The filter element of claim 3 in which the polyolefin particles are polyethylene.

5. The filter element of claim 4 in which the watersoluble salt is selected from sodium carbonate or potassium carbonate.

6. The filter element of claim 3 in which the polyolefin particles are polypropylene.

7. The filter element of claim 6 in which the watersoluble salt is selected from sodium carbonate or potassium carbon-ate.

(References on following page) References Cited UNITED STATES PATENTS Sutter 131-265 Seligman et a1 131-266 Tovey 131--266 Keith et a]. 131-10.9 X Lloyd 131-266 Hughes et a1 131-267 5 MELVIN D. REIN, Primary Examiner.

US. Cl. X.R. 

